Mustard is too well known to require describing. It is an emetic,
diuretic, stimulant, and rubefacient.
It is _used externally_ as a poultice. Mustard poultices are made of
the powder, bread crumbs, and water; or of one part of mustard to two
of flour; or, especially for children, of linseed meal, mixed with a
little of the powder, or having some of the powder slightly sprinkled
on the surface. Sometimes a little vinegar is added under the idea
that it increases the strength of the poultice, but this is not
necessary. In all cases where a stimulant is required, such as sore
throats, rheumatic pains in the joints, cholera, cramps in the
extremities, diarrhoea, and many other diseases. When applied it
should not he left on too long, as it is apt to cause ulceration of
the part. From ten to thirty minutes is quite long enough.
When _used internally_ as an emetic, a large teaspoonful mixed with a
tumbler of warm water generally operates quickly and safely,
frequently when other emetics have failed. In dropsy it is sometimes
given in the form of whey, which is made by boiling half an ounce of
the bruised seeds in a pint of milk, and straining off the curd.
From three to four ounces of this is to be taken for a dose three
times a day.